Screw locking means



Dec. 28, 1948. G. P. LUM 2,457,697

SCREW LOCKING MEANS Filed Sept. 25, 1946 Patented Dec. 28 1948 I answer 4 .SCREWI'QOCKING MEANS iGeorge .E'P :Izum, :South Bend, 11ml, assignornto Bendix viationflorpovation,.south-Bend lnd V acorporationpfinelaware Applicationsepteniber 25, I946,-ZSei'-ial l lo.* 639;204

'4 Claims.

:1 IThe present invention relates 350.. an adjustable stop: for limiting the movement. oi; a ilever. or the like: and/more particularly to an 1 adjustable: zStOD for ilimiting the movement \of *a throttle valve lever on engine carburetors andasmeans for maintainingthe adjustment once theesettingis made.

One of the principal objects .of .the :present invention is l to provide a readily nadjustabletstop for a lever-which requires only-a single'ioperation to completelthe-se'tting.

Another object of the invention is to pprovide a simplified adjustable stop for carburetor levers which can be accurately adjusted and which maintains said adjustment indefinitely without employingeaseparate lockingmeans.

Still another object of the presentlinvention is to provide an adjustable stop for carburetor levers which can be readily-fabricated'with standard equipment without the use of special-diesror jigs. 7

Other objects and advantagesrof the 319118561113 invention will be apparent fromthe fOIIOWi IE'flB- scription and from the accompanying drawings, in which:

Figure 1 is a side elevation of a conventional carburetor showing the fast idle cam and throttle lever assembly in which the present adjustable stop is employed;

Figure 2 is a perspective view of the throttle valve shaft and lever of which the present invention forms an integral part;

Figure F3 is an enlarged view of the adjustable stop shown in Figures 1 and 2.

In the drawings, numeral 2 designates generally a conventional carburetor including an air horn 4, float chamber 6, fuel inlet union 8, throttle body it, having flange l2 and holes l4 to receive bolts for securing the carburetor to the intake manifold of an internal combustion engine (not shown). A throttle valve lever I6 is mounted on one end of a throttle valve shaft 18 and is rigidly secured thereto by riveting the end of said shaft around the adjacent portion of the lever. A rod 20 connecting the throttle valve lever to an accelerating pedal or lever is journaled in hole 22 and is secured in said hole by c'otter pin 28. A fast idle cam 32 and a fast idle lever 34 are mounted on stud 36 and secured in place by hair pin clip 38. Lever 34 and rod 4!! form a one-way connection between the fast idle cam 32 and a choke valve lever 42, said choke valve lever being adapted to be connected to a temperature responsive mechanism (not shown) which adjusts the position of the fast idle cam in l 02 accordance \vith rengine temperature. The 'fast idle :cam thus prevents the ithrottle from completely closing :While attics-engine: is beingcc'ranke'd and :before 'it has become :Warm :after starting, thereby providing an enriched mixture :Ior :the cold engine. The degree to *whichltheithrott-le valve WillxbE :heldopen when .the :enginezismold depenclsguponl the-. setting'of a ithrottle-valve lever stop "mechanism generally 'I'ShOWIl 221F144 .in .(the drawings. .A r-lateral or: lug #46 tis formed integrally with the throttle .valve leverand is provided tvith-a'anainternall-y threaded-holedawhichlis adapted to receive a threadedemember'fifl,such-as a machine or fillister head screw or a threaded pin having aaslot in one end .to permit-adjustment thereof "with a screw driven or similar instrument. One end of screw --50 is adapted :toengage an abutment to :limit thetclosing movementtof -the throttle valve lever, :andin'the present embodiment -.the --abutment is the periphery of the fast idleeam 32iwhichis1adapted to vary the deg ree enclosing ofthe throttle valvein accordanceiwith the engine: temperature and choke .valve'gpositions. After the adjustmenttofscrew 5:01relative' to the -perlphenymf rthetfastaidle lc'amc32 rhas rbeen imade to obtain the desired degree of closing of the throttle valve, said screw is held in the final setting by the frictional engagement of its screw threads with the screw threads on segments 52 and 54 of the marginal portion of arm 46 around hole 48, said segments being separated at one end of said arm by slot 56. The frictional engagement of the threads of the aforementioned elements is accomplished by slightly offsetting the screw threads of one segment from the corresponding threads of the other segment. The resiliency of segments 52 and 54 in their deformed position creates a constant force urging the threads of the segments against the threads of screw 50 which prevents accidental rotation of said screw. The threads are offset by bending either one of said segments to the right or left or by bending both segments in opposite directions, as shown in the drawings, sufiiciently to cause a substantial gripping action between the contacting threads of the segments and screw, but not sufficiently to prevent alignment of corresponding threads of the two arms when the screw is in hole 48. The degree of frictional resistance to rotation of the screw 5!] depends upon the de gree of offset of the corresponding threads of the two segments, as long as the distortion is is not great enough to cause the threads of one segment to align with threads adjacent to the corresponding threads of the other segment.

In the fabrication of the present stop mechanism on the throttle valve lever, the lug 46 is first formed integrally with the throttle valve lever in a, single stamping operation; then hole 48 is drilled in said lug and tapped. Slot 56, which separates segments 52 and 54, is preferably machined in arm 46 after hole 48 has been tapped, but this slot may be formed in the arm during the stamping operation. After hole 48 has been tapped and slot 56 formed in said arm, segments 52 and 54 are permanently deformed relative to one another as clearly shown in Figure 3 of the drawings.

While the two segments are shown separated from one another by slot 56, the threads may be offset without forming said slot between segments 52 and 54. This may be accomplished by upsetting arm 46 after hole 48 has been tapped. Further, the ofiset portion or slot 56 between the two segments may be located on either side of lug 46 instead of at the end of said arm as shown in the drawings. Still further modifications of the present invention will be apparent to those skilled in the art, and the use of any or all the ramifications of the present invention falling within the scope of the appended claims is contemplated. It is understood that the stop mechanism may readily be adapted to many forms of levers or elements of the oscillating or reciproeating type, and the use of the term lever in the appended claims is intended to embrace all such types of movable elements to which the present invention can be adapted.

I claim:

1. An adjustable stop mechanism for a lever comprising an arm, a threaded hole through said arm, a screw in said hole supported by said arm, an abutment for said screw to limit the movement of said lever, the portion of said arm defining said hole being divided into two segments, the threads of one of said segments'being offset in respect to the threads of the other segment, whereby the threads of said hole frictionally engage the threads of said screw.

2. An adjustable stop mechanism for a lever comprising an arm, a threaded hole through said arm, a screw in said hole supported by said arm, an abutment for said screw to limit the movement of said lever, a radial slot extending from said hole dividing said arm into segments, the threads of one of said segments being offset in respect to the threads of the other segment, whereb the threads? of said hole frictionally engage the threads of said screw.

3. An adjustable stop mechanism for a throttle valve lever of a carburetor comprising an arm, a threaded hole through said arm, a screw in said hole supported by said arm, an abutment for said screw to limit the movement of said lever, a single radial slot extending from said hole dividing said arm into two segments, the threads of one of said segments being offset in respect to the threads of the other segment, whereby the threads of said screw frictionally engage corresponding threads of said segments.

4. An adjustable stop mechanism for a throttle valve lever of a carburetor comprising an arm, a threaded hole through said arm, a screw in said hole supported by said arm, a fast idle cam forming an abutment for said screw to limit the movement of said lever, a radial slot extending from said hole dividing said arm into two segments, the threads of one of said segments being offset in respect to the threads of the other segment, whereby the threads of said screw frictionally engage corresponding threads of said segments.

GEORGE P. LUM.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 800,188 Ward Sept. 26, 1905 1,665,807 Dieter Apr. 10, 1928 2,179,380 Nieman Nov. 7, 1939 

